Conveyor belt and module with wear pads

ABSTRACT

A plastic modular conveyor belt constructed of belt modules with wear pads. The belt is supported in the carryway of a conveyor atop linear wearstrips along which the belt&#39;s wear pads slide as the belt advances.

BACKGROUND

The invention relates generally to power-driven conveyors and inparticular to modular plastic conveyor belts.

Modular plastic conveyor belts constructed of rows of plastic beltmodules joined together end to end at hinge joints are used to conveyproducts in many industrial applications. The belts are supported inproduct carryways by wearstrips, typically made of UHMW. As the beltsride along the wearstrips, sliding friction between the undersides ofthe belts and the wearstrips causes the belts to wear. Excessive wearweakens the belt and shortens its effective life.

SUMMARY

One version of a conveyor belt module embodying features of theinvention comprises a module body that extends in length from a firstend to a second end, in width from a first side to a second side, and inthickness from a top side to a bottom side. First hinge elements arespaced apart laterally along the first end of the module body, andsecond hinge elements are spaced apart laterally along the second end ofthe module body. Drive faces extend laterally along the bottom side ofthe module body. One or more wear pads on the bottom side of the modulebody are laterally offset from the drive faces. The wear pads each havea wear surface at the bottom side. The area of the wear surface of eachof the wear pads is greater than the area of any of the first and secondhinge elements at the bottom side.

Another version of a conveyor belt module comprises a module body thatextends in length from a first end to a second end, in width from afirst side to a second side, and in thickness from a top side to abottom side. First hinge elements are spaced apart laterally along thefirst end of the module body, and second hinge elements are spaced apartlaterally along the second end of the module body. Drive faces extendlaterally along the bottom side of the module body. Wear pads on thebottom side of the module body are laterally offset from the drivefaces. The wear pads each have a wear surface at the bottom side made ofa different material from the rest of the module body.

In another aspect a conveyor embodying features of the inventioncomprises a modular conveyor belt constructed of a series of rows of oneor more belt modules hingedly connected end to end at hinge jointsbetween consecutive rows. At least some of the rows include drive facesthat extend laterally along a bottom side of the modular conveyor beltand wear pads on the bottom side of the modular conveyor belt laterallyoffset from the drive faces. The wear pads each have a wear surface atthe bottom side of the modular conveyor belt. An upper carryway includeswearstrips spaced apart across the width of the carryway. The wearstripsextend linearly along the length of the carryway to support the modularconveyor belt. A drive element engages the drive faces to drive themodular conveyor belt in a direction of belt travel along the carryway.The wear pads on the bottom side of the modular conveyor belt arearranged in columns aligned with the wearstrips so that the wearsurfaces ride on the wearstrips as the modular conveyor belt is drivenin the direction of belt travel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of a plastic conveyor belt module embodyingfeatures of the invention including a wear pad.

FIG. 2 is a bottom plan view of the module of FIG. 1 .

FIG. 3 is an isometric view of the bottom sides of two modules as inFIG. 2 joined together.

FIG. 4 is an oblique view of the top sides of the modules of FIG. 3 atopwearstrips.

FIG. 5 is a side elevation view of a modular plastic belt conveyorconstructed of modules as in FIG. 1 .

FIG. 6 is a side elevation view of a module as in FIG. 1 in which thewear surface is made of a different material from the rest of themodule.

FIG. 7 is an exploded side elevation view of a module as in FIG. 1 witha detachable wear surface.

FIG. 8 is a front elevation cross section of a wear strip supporting awear pad as in FIG. 4 in which the wear pad has guides.

FIG. 9 is an axonometric view of the bottom side of another version of aconveyor belt module embodying features of the invention.

FIG. 10 is a front elevation view of a belt module as in FIG. 9supported on wearstrips.

FIG. 11 is an enlarged bottom plan view of the outer side of a module asin FIG. 2 partly cut away to show a wear indicator.

FIG. 12 is a bottom plan view of a wear pad as in FIG. 1 with a groovedbottom with a wear indicator.

FIGS. 13A and 13B are bottom and top isometric views of a version of abelt edge module embodying features of the invention.

FIGS. 14A and 14B are bottom and top axonometric views of anotherversion of an edge module embodying features of the invention.

DETAILED DESCRIPTION

FIGS. 1 and 2 are top and bottom views of a conveyor belt moduleembodying features of the invention. The module 20 is a plastic beltmodule molded out of a thermoplastic polymer, such as polyethylene,polypropylene, acetal, or a composite polymer. The module body extendsin length from a first end 22 to a second end 23, in width from a firstside 24 to a second side 25, and in thickness from a top side 26 to abottom side 27. The top side 26 has a conveying surface 21, and thebottom side 27 is the drive side. A plurality of first hinge elements 28are spaced apart laterally across the width of the module body 20aligned along the first end 22. A plurality of second hinge elements 29are spaced apart laterally aligned along the second end 23 of the modulebody 20. In this version the first and second hinge elements are thesame width. But their widths could differ. The first hinge elements 28are laterally offset from the second hinge elements 29 to facilitate theconstruction of a conveyor belt from the modules 20.

The belt module 20 shown in FIGS. 1 and 2 has three wear pads: twooutside wear pads 30 and an interior wear pad 32. Of course, a modulecould have more than one interior wear pad, such as in the case of awider belt module. Or a small module, such as an edge module, could haveonly a single wear pad. The wear pads 30, 32 have a wear surface 34 atthe bottom side 27 of the module body 20. In this version the wearsurface 34 is a flat closed surface. But in other versions the wearsurface 34 could be interrupted by holes, slits, or other openings thatextend through the thickness of the wear pads to provide passages forairflow or drainage, for example. The interior wear pad 32 includes apad hinge element 36 at the first end 22 of the module 20. The pad hingeelement 36 is aligned with the first hinge elements 28 but isdistinguished from the first hinge elements by providing a continuationof the wear pad's wear surface 34 at the module's bottom side 27 and ofthe conveying surface 21 at the module's top side 26. In this versionthe lateral extent and the area of the wear surface 34 of each of thewear pads 30, 32 are greater than the lateral extent and the bottom areaof any of the first and second hinge elements 28, 29 and of any otherindividual structural elements on the bottom side 27 of the module body20, other than the pad hinge element 36. The lateral extent of the padhinge element 36 is at least as wide as the wear surface 34.

Drive bars 38 are laterally elongated along the bottom side 27 of themodule body 20. The drive bars 38 form drive faces 40, 41 on one or bothsides that can receive a drive force from a drive sprocket. In thedepicted version the drive bars 38 are centrally located midway betweenthe first and second ends 22, 23 of the module body 20. But they couldbe located closer to one of the ends than to the other. Or, instead ofbeing formed on drive bars, the drive faces could be formed on theleading or training walls of drive pockets at the bottom side of themodule. The drive bars 38 shown in FIG. 2 , which extend laterally fromone of the wear pads 30 to another 32, are laterally offset from thewear pads 30, 32. And the drive bars 38 extend downward to the samelevel as the wear surfaces 34 of the wear pads 30, 32 in this version,in which that level is the bottom-most level of the module. But thedrive bars 38 could terminate inward of the wear surfaces 34. Recessedregions 42 at the bottom side 27 between the drive bars 38 and the hingeelements 28, 29 permit access to drive-sprocket teeth to engage thedrive faces 40, 41 of the drive bars. End walls 43 of the recessedregions 42 formed by the wear pads 30, 32 limit the lateral wander of aconveyor belt constructed of the modules 20 by confining an axiallyfixed sprocket to the recessed region to provide belt tracking.

Consecutive conveyor belt modules 20 are connected end to end as shownin FIG. 3 to form a conveyor belt. The first hinge elements 28 and thepad hinge elements 36 interleave with the second hinge elements 29 of aconsecutive module 20. In this version, the interleaved hinge elements28, 29, 36 have aligned openings 44 that receive a hinge rod to form ahinge joint 46 connecting consecutive rows of modules. Spaces 48 betweenconsecutive hinge elements 28, 29, 36 are slightly wider than the hingeelements to receive the hinge elements of the connected row of beltmodules. When the modules are connected, the wear pads 30, 32 arearranged in laterally spaced columns 50 that extend along the length ofthe belt.

As shown in FIG. 3 , the columns of wear pads 30, 32 align with and rideon linear wearstrips 52 that extend along the length of the upperconveyor carryway. The wearstrips 52 support the belt in the carrywayand provide a sliding surface along which the wear surfaces of the wearpads ride as the belt is driven in a direction of belt travel 54. Thus,the wear pads 30, 32 are the only part of the belt in contact with thewearstrips 52.

An endless conveyor belt loop constructed of linked conveyor beltmodules as in FIGS. 1-4 is shown in a conveyor 55 in FIG. 5 . The belt56 is trained around drive and idle sprockets 58, 59. Teeth on thesprockets engage the drive faces of the modules to drive the belt 56 inthe direction of belt travel 54. The belt 56 is shown supported bywearstrips 52 on the upper carryway 50. The belt 56 returns from thedrive sprockets 58 to the idle sprockets 59 along a lower returnway 61.Each belt row 62 may include one or more belt modules 20 as in FIGS. 1-4, including laterally shortened versions of those modules in a bricklaidbelt pattern.

Because the wear pads slide on the wearstrips, they are subjected togreater frictional wear than the rest of the module body. FIG. 6 shows awear pad 64 whose bottom wear surface 66 is made of a wear-resistantmaterial, such as nylon, acetal, PEEK, and UHMW, permanently fastened tothe module body 68 by overmolding, co-molding, ultrasonic welding,gluing, or mechanical attachment, for example. The wear-resistantmaterial may be chosen for its durability or its low-friction propertiesand may allow the wearstrips to be made of stainless steel. The rest ofthe module body 68 is made of a different thermoplastic material such aspolyethylene, polypropylene, acetal, or other polymeric materialsconventionally used to make plastic conveyor belt modules.

A detachable wear surface 70 is shown in FIG. 7 . The wear surface 70has attachment elements in the form of expandable tabs 72 that mate withattachment elements in the form of receptacles 74. In this example thetabs 72 snap into place in the receptacles 74. But any sort of matingattachment elements that releasably fasten in any way may be used toallow for easy replacement of a worn wear surface 70. The wear surface70 may be made of a wear-resistant material. The module body 76 has arecess 78 at the bottom in which the wear surface 70 resides.

FIG. 8 shows another version of a wear pad. In this version the wear pad80 has depending guides 82 at each side flanking a wear surface 84riding along a wearstrip 86. The guides 82 limit lateral wander of theconveyor belt to the width of the slot 88 formed between the twodepending guides 82. Thus, the guides 82 provide belt tracking.

Another version of a conveyor belt module is shown in FIG. 9 . The beltmodule 90 has outer wear pads 92 and an inner wear pad 93 whose wearsurfaces 94 are at a different level from the bottoms of the drive bar96 and the hinge elements 98, which define the bottom-most level of themodule. Otherwise the module 90 is like the belt module 20 of FIGS. 1and 2 . Because the wear surfaces 94 of the wear pads 92, 93 areindented upward from the bottom-most level 100 of the module 90 as shownin FIG. 10 , a conveyor belt constructed of the modules 90 forms alongitudinal slot 102 in which wear strips 104 are received. Thedownward extension of the drive bars 96 and the hinge elements 98′bounding the wear pads 92, 93 past their indented wear surfaces 94limits lateral wander of the conveyor belt by contact with the sides ofthe wear strips 104.

FIGS. 11 and 12 show two examples of wear indicators built into wearpads. In FIG. 11 a wear pad 106 has an internal layer 108 of a differentcolor than the original outer wear surface 110. As the wear surface 110wears, the internal layer of a different color becomes visible toindicate wear of the wear pad 106. In FIG. 12 a wear surface 112 isinterrupted by grooves 114 that are elongated in the direction of belttravel 54. Slightly raised portions 116 of the base of the grooves serveas wear indicators like those in tire treads. As the wear surface 112wears, the distance from the top of the wear indicators 116 to the wornwear surface decreases so that wear can be identified, and correctiveaction taken.

Another version of a belt module with a different outside edge is shownin FIGS. 13A and 13B. The module 120 is shown as an edge module with awear pad 122 at an outer side 124 and suitable for constructing abricklaid conveyor belt. But a wider module with a similar outer side atthe other side, with or without interior wear pads, could be made forconstructing non-bricklaid belts having a single module forming eachbelt row. The module 120 has first and second hinge elements 28, 29 anda drive bar 38 like the module of FIG. 2 . The wear pad 122 has a slot128 extending at an angle from the wear pad's wear surface 126 along aninner wall 129 of the wear pad for a rod-removal tool, such as ascrewdriver, to access the end of a hinge rod and bend it away from astop formed by the inner wall and toward the level of the wear surfaceso that the rod can be removed from the hinge elements. The inner wall129, which presents a stop that is in line with and faces the line offirst hinge elements 28, prevents the hinge rod from working its way outof the line of hinge elements during operation of the conveyor belt. Thelateral extent and the area of the wear surface of the wear pad 122 aregreater than those of the hinge elements 28, 29.

A belt module 130 with another version of a wear pad 132 at an outerside 134 is shown in FIGS. 14A and 14B. The wear pad's wear surface atthe bottom of the module 130 has a lateral extent and an area greaterthan those of first and second hinge elements 28, 29. The wear pad 132tapers away from the wear surface 136 along a ramp 138 in line with andfacing the aligned first hinge elements 28. The ramp 138 is shown asconcavely curved, but could also be flat. The ramp 138 provides a slidesurface along which the end of a hinge rod can slide when the rod ispushed out through the hinge elements during manual removal. Like themodule of FIGS. 13A and 13B, the belt module 130 can be a narrow edgemodule as shown or it can be a wider module with similar wear pads 132at both outer sides.

What is claimed is:
 1. A conveyor belt module comprising: a module bodyextending in length from a first end to a second end, in width from afirst side to a second side, and in thickness from a top side to abottom side; a plurality of first hinge elements spaced apart laterallyalong the first end of the module body; a plurality of second hingeelements spaced apart laterally along the second end of the module body;drive faces extending laterally along the bottom side of the modulebody; one or more wear pads on the bottom side of the module bodylaterally offset from the drive faces and the first and second hingeelements; wherein the wear pads each have a wear surface at the bottomside; and wherein the area of the wear surface of each of the wear padsis greater than the area of any of the first and second hinge elementsat the bottom side.
 2. A conveyor belt module as claimed in claim 1wherein the one or more wear pads include a first solid wear pad at thefirst side of the module body and a second solid wear pad at the secondside of the module body.
 3. A conveyor belt module as claimed in claim 1wherein at least one of the wear pads includes a pad hinge element atthe first end of the module body that forms a continuation of the wearsurface of the wear pad and whose lateral extent is at least as wide asthe lateral extent of the wear pad.
 4. A conveyor belt module as claimedin claim 1 wherein the drive faces are formed on laterally elongateddrive bars that extend to the level of the wear surfaces at the bottomside of the module body.
 5. A conveyor belt module as claimed in claim 1wherein the drive faces are formed on elongated drive bars that extendlaterally from one of the wear pads to another of the wear pads.
 6. Aconveyor belt module as claimed in claim 1 wherein the one or more wearpads are detachable from the module body.
 7. A conveyor belt module asclaimed in claim 1 wherein a portion of the wear pads including the wearsurface is made of a wear-resistant material and the rest of the modulebody is made of a different material.
 8. A conveyor belt module asclaimed in claim 1 wherein a portion of the wear pads including the wearsurface includes a wear indicator that indicates wear of the wearsurface.
 9. A conveyor belt module as claimed in claim 8 wherein thewear surface includes one or more grooves and the wear indicatorcomprises a raised portion of the base of the grooves.
 10. A conveyorbelt module as claimed in claim 8 wherein the wear indicator comprises alayer of the wear pad interior of the wear surface that differs in colorfrom the wear surface when not worn.
 11. A conveyor belt module asclaimed in claim 1 wherein the wear surface of the wear pads is a closedsurface.
 12. A conveyor belt module as claimed in claim 1 wherein thewear surfaces of the wear pads define the bottom-most level of thebottom side of the module body.
 13. A conveyor belt module as claimed inclaim 1 wherein the wear surfaces of the wear pads are indented upwardfrom the bottom-most level of the bottom side of the module body.
 14. Aconveyor belt module as claimed in claim 1 wherein one of the wear padsforms the first side of the conveyor belt module and has an inner wallforming a stop in line with and facing the first hinge elements.
 15. Aconveyor belt module as claimed in claim 1 wherein one of the wear padsforms the first side of the conveyor belt module and has a ramp in linewith and facing the first hinge elements and extending to the wearsurface of the wear pad.
 16. A conveyor belt module as claimed in claim1 wherein the lateral extent of the wear surface of each of the wearpads is greater than the lateral extent of any of the first and secondhinge elements at the bottom side.
 17. A conveyor belt modulecomprising: a module body extending in length from a first end to asecond end, in width from a first side to a second side, and inthickness from a top side to a bottom side; a plurality of first hingeelements spaced apart laterally along the first end of the module body;a plurality of second hinge elements spaced apart laterally along thesecond end of the module body; drive faces extending laterally along thebottom side of the module body; a plurality of wear pads on the bottomside of the module body laterally offset from the drive faces and thefirst and second hinge elements; wherein the wear pads each have a wearsurface at the bottom side made of a different material from the rest ofthe module body.
 18. A conveyor comprising: a modular conveyor beltcomprising a series of rows of one or more belt modules hingedlyconnected end to end at hinge joints between consecutive rows; whereinat least some of the rows include: first hinge elements spaced apartalong first ends of the row and second hinge elements spaced apart alongopposite second ends of the row; hinge rods extending through theinterleaved first and second hinge elements of consecutive rows toconnect consecutive rows together at the hinge joints; drive facesextending laterally along a bottom side of the modular conveyor belt; aplurality of wear pads on the bottom side of the modular conveyor beltlaterally offset from the drive faces and the first and second hingeelements; wherein the wear pads each have a wear surface at the bottomside of the modular conveyor belt; an upper carryway including aplurality of wearstrips spaced apart across the width of the carrywayand extending linearly along the length of the carryway to support themodular conveyor belt; a drive element engaging the drive faces to drivethe modular conveyor belt in a direction of belt travel along thecarryway; wherein the wear pads on the bottom side of the modularconveyor belt are arranged in columns aligned with the wearstrips sothat the wear surfaces ride on the wearstrips as the modular conveyorbelt is driven in the direction of belt travel.
 19. A conveyor asclaimed in claim 18 wherein the drive faces are formed on drive barsthat are elongated in a direction perpendicular to the direction of belttravel and that extend to the bottom-most level of the bottom side ofthe modular conveyor belt.
 20. A conveyor as claimed in claim 18 whereinat least some of the rows have recessed regions on the bottom sideadjacent the drive faces to receive the teeth of sprockets, wherein therecessed regions are bounded by end walls on the sides of the wear padsto limit lateral wander of the modular conveyor belt relative to anaxially fixed sprocket.
 21. A conveyor as claimed in claim 18 whereinevery row includes a plurality of the wear pads.
 22. A conveyor asclaimed in claim 18 wherein the carryway wearstrips include outerwearstrips disposed along outer sides of the carryway and wherein thecolumns of wear pads on the modular conveyor belt include outer columnsof wear pads whose wear surfaces ride on the outer wearstrips.
 23. Aconveyor as claimed in claim 18 wherein each of the rows of belt modulescomprises: first hinge elements spaced apart along first ends of the rowand second hinge elements spaced apart along opposite second ends of therow; a pad hinge element at the first end of the row on one or more ofthe wear pads that forms a continuation of the wear surface.
 24. Aconveyor as claimed in claim 23 wherein the area of the pad hingeelement and the wear pad is greater than the area of any of the firsthinge elements at the bottom side of the conveyor belt.
 25. A conveyoras claimed in claim 18 wherein the plurality of wear pads have guidesextending downward on opposite sides of the wear surfaces that cooperatewith the wearstrips to limit lateral wander of the conveyor belt on thecarryway.
 26. A conveyor as claimed in claim 18 wherein each row of beltmodules has wear pads forming outer sides of the conveyor belt.
 27. Aconveyor belt module as claimed in claim 26 wherein the wear padsforming the outer sides of the conveyor belt each have a ramp in linewith and facing the interleaved first and second hinge elements andextending to the wear surface of the wear pad to provide a slidingsurface along which the hinge rod can be slid during removal from thehinge joint.
 28. A conveyor as claimed in claim 26 wherein the wear padsforming the outer sides of the conveyor belt each have an inner wallforming a stop in line with and facing the interleaved first and secondhinge elements to prevent the hinge rod connecting the interleaved firstand second hinge elements from working its way out of the hinge jointduring operation of the conveyor.
 29. A conveyor as claimed in claim 28wherein the wear pads forming the outer sides of the conveyor belt eachhave a slot extending from the wear surface of the wear pad along theinner wall for a removal tool to access the hinge rod.